Carburetor



NOV. 24, 1936. w H WEBER 2,062,260

CARBURETOR Filed Dec. 13, 1953 HUI! n INVENTOR m AJmd Patented Nov. 24,1936 UNITED STATES PATENT OFFICE" Application December 13, 1933, SerialNo. 702,103

7' Claims.

My invention relates to new and useful improvements in carburetors, andmore particularly to a carburetor for supplying a mixture of air andfuel to an internal combustion engine.

In cold weather operation on starting, the fuel mixture must beexceedingly rich in fuel in order to insure firing of the engine, but assoon as the engine is fired this overrich mixture will result installing of the engine, and therefore the ratio of fuel to air must bedecreased. It is therefore one object of my invention to provide meansoperable automatically to reduce the richness of the fuel mixture assoon as the engine has fired and is operating under its own power.

Another object is to provide a carburetor having automatic meansresponsive to suction and temperature for controlling the ratio of fuelto air at closed throttle position or engineidling speed.

Another object is to provide the throttle valve with the automatic fuelmixture controlling means.

The invention consists in the improved construction and combination ofparts, to be more fully described hereinafter and the novelty of whichwill be particularly pointed out and distinctly claimed.

In the accompanying drawing, to be taken as a part of thisspecification, I have fully and clearly illustrated a preferredembodiment of my invention, in which drawing:

Figure l is a view in side elevation and partly in vertical, centralsection of a carburetor embodying my invention;

Fig. 2 is a detail top plan view of the carbu retor throttle body;

Fig. 3 is an enlarged detail view insection of certain of the structureshown in Fig. 1, and

Fig. 4 is a diagrammatic view showing a fuel supply means embodied in mycarburetor.

Referring to the drawing by characters of reference, l designatesgenerally a carburetor comprising a casing having a, mixture passageway2 therethrough and provided with an air inlet 3 and a mixture outlet 4.The passageway 2 includes a mixing chamber 5 supplied with air from theinlet 3 and with fuel from a main fuel nozzle, not shown, which issupplied from the constant level chamber 6. In the passageway 2, thereis a throttle valve 1 of the usual butterfly or disc type, secured on ashaft 8 journaled in the side walls of the casing l and which serves tocontrol the discharge of the fuel mixture from the outlet 4. Thepassageway 2 is provided with a supplemental fuel inlet 9 discharginginto the outlet 4 posterior of the throttle valve 1 and fed with fuelthrough a conduit l0 supplied from the chamber 6. In the conduit Illthere is a control valve Ill rotatably supported in a valve housing lorigid with the casing l. The throttle l carries a valve casing II whichis preferably screw-threaded, as at I 2, or otherwise rig-,

idly secured in an aperture through the throttle valve. The valve casingII is hollow, being closed at its lower end by an annular member l3having -a central valve port l4 therethrough establishing communicationbetween the mixing chamber side of the throttle valve and. the interiorof the casing II. The member l3 serves also as a valve seat forcooperation with a reciprocable valve disc or member l5 positionedwithin the casing ll and which seats on the member l3 to close the portM. The valve member I5 is normally held in port closing position andagainst the member I 3 by a helical coil spring 16 positioned in thevalve casing chamber H and held under compression between the member l5and the upper end wall I! of the valve casing. Through the end wall I!there is a valve port l8 establishing communication between the valvecasing chamber 1 I on the passageway 2 on the outlet sideof thethrottle-valve so that the ports l4 and I8 together with the chamber llof the valve casing provide a by-pass passageway from the mixing chamber5 to the outlet 4 when the throttle valve is substantially in closed oridling position.

The port 3 is controlled by temperature responsivelmeans comprising avalve member l9 carried by one end of a thermostatic element 20,

the throttle valve, as clearly indicated in Fig. 1.

The strip 20 is preferably bent, as'at 22 and 23, so that its free endportion is in spaced, substantially parallel relation to the plane ofthe throttle valve 1 whereby the movement of the strip in response totemperature change will move the valve member I9 substantially normal tothe plane of its valve seat formed by the outlet end of the port H3.

The operation of my carburetor is as follows: When the temperaturewithin the passageway 2 and adjacent the throttle valve is below that atwhich the liquid fuel will mix efficiently with the air supplied to thepassageway 2, the temperature responsivemeans 20 will be spaced from itsseat on end wall ll, as shown, so that the port IE will be open. Iftemperature in the passageway 2 is too low for eflicient mixing of theair and fuel,

some means must be provided to increase the ratio now cranked forstarting, with the throttle valve 1 in closed idling position, as shown,and with valve Ill opened, fuel will be fed to the outlet 4 through theconduit IO' from the reservoir 6, which supplemental fuel will be mixedwith the small quantity of air passing the circumferential edge of thethrottle valve to provide an exceedingly rich fuel mixture for enginestarting. The spring 16 exerts sufiicient force against the valve memberI5 to hold the Valve member in closed position against the pressure inthe mixing chamber 5, tending to force the same to open position. Assoon as the engine fires and is operating under its own power, thesuction or decrease in pressure in the outlet Q will permit the fluidpressure in the mixing chamber 5 acting through port 14 on valve disc Hito overcome the spring l6 and move the valve member l5 to open position.When the valve member l5 opens, air will be by-passed through thethrottle valve passageway [4, li I8 sufficient to decrease the overrichstarting mixture and provide the desired ratio of fuel to air for cold,idling engine operation. Also, as soon as the engine is operating underits own power, the conduit valve Ill will preferably be closed so thatthe fuel mixture for engine idling operation will be supplied from themixing chamber 5, the by-pass passageway through the throttle valveserving to provide the necessary increased volume of fuel mixturecomprising air from the main inlet 2 and fuel from the main nozzle toprevent stalling of the engine. When the temperature in the passageway 2adjacent the throttle valve has increased sufficiently to provide forefficient mixing of the air and fuel from the main inlets, thetemperature responsive means 20 will move the valve I9 to close the portl8 so that the volume of fuel mixture will be cut down and the enginewill be operating at its normal idling speed supplied by the fuelmixture which passes the circumferential edge of the throttle valve. Theby-pass passage-- way through the throttle valve will be maintainedclosed by the valve l9 as long as the predetermined higher temperatureis maintained but will act to open the port 18 automatically should thetemperature drop sufficiently with the throttle valve in idling positionto cause stalling of the engine without the increased quantity of fuelmixture permitted by the by-pass passageway. It will be noted that thebimetal strip 20 serves when the throttle valve is in idling position tothrottle the flow through the by-pass passageway so that the quantity offuel mixture supplied to the engine will vary inversely with a rise intemperature thereby maintaining the quantity of fuel supplied inproportion to the minimum demand of the engine for idling speed inaccordance with temperature.

The present invention is shown as embodied in a carburetor such as isdisclosed in my copending application S. No. 417,609 filed December 31,1929, which matured to Patent No. 1,981,483 granted November 24, 1934,to which reference may be had if desired for a more complete descriptionof the carburetor illustrated herein.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said valve having a port therethrough, anormally closed pressure responsive valve controlling flow through saidport, and temperature responsive means also controlling flow throughsaid port.

2. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said valve having a port therethrough, anormally closed pressure responsive valve controlling flow through saidport, temperature responsive means also controlling flow through saidport, and means to supply fuel to said passageway on the outlet side ofsaid throttle valve.

3. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said valve having a port therethrough, anormally closed pressure responsive valve controlling fiow through saidport, a spring normally urging said responsive valve to closed position,and temperature responsive means also controlling flow through saidport.

4. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said valve having a port therethrough, anormally closed pressure responsive valve controlling fiow through saidport, a second valve normally open and controlling flow through saidport, and thermostatic means operable to move said last-named valve toclosed position.

5. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said valve having a port therethrough, a valvecasing carried by said throttle valve, said throttle valve and saidvalve casing having a passageway therethrough communicating with saidthrottle port to permit flow through said mixture passageway when saidthrottle valve is closed, a valve in said valve casing, a spring in saidvalve casing normally urging said last-named valve to closed position, anormally open valve controlling flow through said valve casing, andtemperature responsive means to close said last-named valve.

6. A carburetor, comprising a casing having a mixture passagewayprovided with an outlet, a throttle valve in said passageway andcontrolling said outlet, said throttle valve having a by-pass passagewaytherethrough, a pressure responsive valve normally closing said by-passpassageway, a bimetallic strip element secured at one end to saidthrottle valve, and a normally open valve carried by said element andcontrolling said bypass passageway, said last-named valve being moved toclosed position by said element upon predetermined temperature in saidcasing.

7. A carburetor for supplying a fuel mixture to an internal combustionengine, comprising a casing having a mixture passageway therethrough, athrottle valve controlling the discharge of fuel mixture from saidpassageway, said throttle valve having a by-pass passageway, a suctionoperable valve controlling said by-pass passageway, a spring normallyacting to hold said by-pass valve closed at engine cranking speeds whensaid throttle valve is closed but overcome by suction at engine idlingspeeds to permit opening of said bypass valve, and temperatureresponsive means operable to close said by-pass passageway when thetemperature in said mixture passageway reaches a predetermined degree.

WALTER H. WEBER.

